Systems and methods for ofdma and sc-fdma switching

ABSTRACT

A method for selecting an uplink modulation scheme may include receiving downlink control information (DCI). The format of the DCI may be decoded. The uplink modulation scheme may be determined according to the format of the DCI. The uplink modulation scheme may be selected. An uplink signal may be transmitted according to the uplink modulation scheme.

TECHNICAL FIELD

The present disclosure relates generally to communications and wirelesscommunications systems. More specifically, the present disclosurerelates to systems and methods for OFDMA and SC-FDMA switching.

BACKGROUND

Wireless communication devices have become smaller and more powerful inorder to meet consumer needs and to improve portability and convenience.Consumers have become dependent upon wireless communication devices suchas cellular telephones, personal digital assistants (PDAs), laptopcomputers, and the like. Consumers have come to expect reliable service,expanded areas of coverage, and increased functionality.

A wireless communication device may be referred to as user equipment, amobile station, a subscriber station, an access terminal, a remotestation, a user terminal, a terminal, a subscriber unit, etc. The term“user equipment” (UE) will be used herein.

A wireless communication system may provide communication for a numberof cells, each of which may be serviced by a Node B. A Node B may be afixed station that communicates with UEs. A Node B may alternatively bereferred to as a base station, an access point, or some otherterminology. The term “Node B” (NB) will be used herein.

UEs may communicate with one or more Node Bs via transmissions on theuplink and the downlink. The uplink (or reverse link) refers to thecommunication link from the UEs to the Node B, and the downlink (orforward link) refers to the communication link from the Node B to theUEs. A wireless communication system may simultaneously supportcommunication for multiple UEs.

Wireless communication systems may be multiple-access systems capable ofsupporting communication with multiple users by sharing the availablesystem resources (e.g., bandwidth and transmit power). Examples of suchmultiple-access systems include code division multiple access (CDMA)systems, time division multiple access (TDMA) systems, frequencydivision multiple access (FDMA) systems, single carrier frequencydivision multiple access (SC-FDMA) systems, clustered SC-FDMA, NxSC-FDMA(a natural number N times single carrier frequency division multipleaccess), and orthogonal frequency division multiple access (OFDMA)systems.

The 3rd Generation Partnership Project, also referred to as “3GPP,” is acollaboration agreement that aims to define globally applicableTechnical Specifications and Technical Reports for 3rd GenerationSystems. 3GPP Long Term Evolution (LTE) is the name given to a projectto improve the Universal Mobile Telecommunications System (UMTS) mobilephone or device standard to cope with future requirements. The 3GPP maydefine specifications for the next generation mobile networks, systems,and devices. In one aspect, UMTS has been modified to provide supportand specification for the Evolved Universal Terrestrial Radio Access(E-UTRA) and Evolved Universal Terrestrial Radio Access Network(E-UTRAN).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a wireless communication system in which the presentsystems and methods may be practiced;

FIG. 2 illustrates a wireless communication system in which the presentsystems and methods may be practiced;

FIG. 3 illustrates various components that may be utilized to implementthe present systems and methods;

FIG. 4 is a flow diagram illustrating a method for switching betweenSC-FDMA and OFDMA as the uplink modulation scheme;

FIG. 5 is a flow diagram illustrating a more detailed method forswitching between SC-FDMA and OFDMA as the uplink modulation scheme;

FIG. 6 is a flow diagram illustrating an alternative method forswitching between SC-FDMA and OFDMA as the uplink modulation scheme;

FIG. 7 is a flow diagram illustrating another method for switchingbetween SC-FDMA and OFDMA as the uplink modulation scheme;

FIG. 8 illustrates L1/L2 signaling between the Node B and the UE;

FIG. 9 illustrates the resource block (RB) allocation of an LTE uplinktransmission;

FIG. 10 illustrates the RB allocation of an LTE-Advanced uplinktransmission;

FIG. 11 is a block diagram of a UE in accordance with one configurationof the described systems and methods; and

FIG. 12 is a block diagram of a base station in accordance with oneconfiguration of the described systems and methods.

DETAILED DESCRIPTION

A method for selecting an uplink modulation scheme may include receivingdownlink control information (DCI). The format of the DCI may bedecoded. The uplink modulation scheme may be determined according to theformat of the DCI. The uplink modulation scheme may be selected. Anuplink signal may be transmitted according to the uplink modulationscheme.

In various implementations, the uplink modulation scheme may be singlecarrier frequency division multiple access (SC-FDMA), orthogonalfrequency division multiple access (OFDMA), N (N is a natural number)times single carrier frequency division multiple access (NxSC-FDMA), orclustered single carrier frequency division multiple access (ClusteredSC-FDMA). The method may be carried out by a user equipment (UE) usingL1/L2 signaling.

Decoding the format of the DCI may include determining if the DCIincludes a non-contiguous resource block (RB) allocation. Decoding theformat of the DCI may also include determining if the DCI includes aprecoding matrix index (PMI). Additionally, decoding the format of theDCI may include determining if the DCI includes only one modulation andcoding scheme (MCS). The uplink modulation scheme may be selectedaccording to a DCI switching bit.

The uplink modulation scheme may be orthogonal frequency divisionmultiple access (OFDMA) or clustered single carrier frequency divisionmultiple access (Clustered SC-FDMA) or N (N is a natural number) timessingle carrier frequency division multiple access (NxSC-FDMA) if the DCIformat includes non-contiguous RB (resource block) allocation and/or apreceding matrix index (PMI). The uplink modulation scheme may be singlecarrier frequency division multiple access (SC-FDMA) if the DCI formatdoes not include non-contiguous RB allocation or a PMI.

The UE may be configured for operation in a 3GPP LTE-Advanced system.The uplink modulation scheme may be orthogonal frequency divisionmultiple access (OFDMA) or clustered single carrier frequency divisionmultiple access (Clustered SC-FDMA) or N (N is a natural number) timessingle carrier frequency division multiple access (NxSC-FDMA) if the DCIformat includes non-contiguous RB (resource block) allocation. Theuplink modulation scheme may be single carrier frequency divisionmultiple access (SC-FDMA) if the DCI format includes contiguous RBallocation.

The uplink modulation scheme may be orthogonal frequency divisionmultiple access (OFDMA) or clustered single carrier frequency divisionmultiple access (Clustered SC-FDMA) or N (N is a natural number) timessingle carrier frequency division multiple access (NxSC-FDMA) if the DCIformat includes non-contiguous RB (resource block) allocation. Theuplink modulation scheme may be single carrier frequency divisionmultiple access (SC-FDMA) if the DCI format does not includenon-contiguous RB allocation and a preceding matrix index (PMI). Theuplink modulation scheme may be either OFDMA or SC-FDMA depending on aswitching bit in the DCI if the DCI format includes contiguous RBallocation and a preceding matrix index (PMI).

Determining the uplink modulation scheme may include comparing the DCIformat to an uplink data transmission table. Formats in the uplink datatransmission table may be used to puncture resources allocated to thephysical uplink control channel (PUCCH). Puncturing resources may becommunicated to the UE via radio resource control (RRC) signaling. RRCsignaling may mean “Maximum SRS bandwidth” and/or “PUCCH Resource size”on a broadcast channel (BCH).

A user equipment (UE) that is configured for selecting an uplinkmodulation scheme is disclosed. The user equipment includes a processorand memory in electronic communication with the processor. Downlinkcontrol information (DCI) is received. A format of the DCI is decoded.An uplink modulation scheme is determined according to the format of theDCI. The uplink modulation scheme is selected. An uplink signal istransmitted according to the uplink modulation scheme.

A base station that is configured for selecting an uplink modulationscheme in a wireless communications system is disclosed. The basestation includes a processor and memory in electronic communication withthe processor. Executable instructions are stored in the memory. Alocation of a user equipment (UE) is determined. An uplink modulationscheme is determined to be used by the UE. A format for downlink controlinformation (DCI) is selected. The format of the DCI corresponds to theuplink modulation scheme. The DCI is transmitted to the UE.

The base station may be configured for operation in a 3GPP LTE-Advancedsystem. The format of the DCI may be selected based on a transmissionmode of the UE. The format of the DCI may be selected based on thelocation of the UE. The instructions may be executable to transmit theDCI to the UE using L1/L2 signaling.

A computer readable medium is also disclosed. The computer-readablemedium comprises executable instructions. Downlink control information(DCI) is received. A format of the DCI is decoded. An uplink modulationscheme is determined according to the format of the DCI. The uplinkmodulation scheme is selecting. An uplink signal is transmittedaccording to the uplink modulation scheme.

The uplink transmission scheme for a 3GPP LTE system is based onSC-FDMA. In 3GPP LTE-Advanced, OFDMA may be added as an uplinktransmission scheme in addition to SC-FDMA. NxSC-FDMA and ClusteredSC-FDMA may also be added as additional uplink transmission schemes inLTE-Advanced. In an OFDM system, the available spectrum is divided intomultiple carriers, called sub-carriers. Each of these sub-carriers isindependently modulated by a low rate data stream.

Orthogonal frequency division multiple access (OFDMA) allows the accessof multiple users on the available bandwidth by using differentorthogonal frequencies to transmit information. OFDMA sends the signalsthrough an IFFT (inverse Fourier Transform) before modulation andtransmission. Each user may be assigned a specific time-frequencyresource. The data channels may be shared channels; i.e., for eachtransmission time interval, a new scheduling decision may be takenregarding which users are assigned to which time/frequency resourcesduring that transmission time interval. A radio frame may be dividedinto a certain number of equally sized slots. A sub-frame may consist oftwo consecutive slots. OFDMA systems may have a high peak-to-averagepower ratio (PAPR).

Single carrier frequency division multiple access (SC-FDMA) also allowsthe access of multiple users on the available bandwidth by usingdifferent orthogonal frequencies to transmit information. However,unlike OFDMA, SC-FDMA sends the signals through a DFT (discrete FourierTransform) before the IFFT, thereby reducing the PAPR but increasing thecomplexity. SC-FDMA also requires additional complexity at the receiver.

Clustered SC-FDMA is very similar to SC-FDMA. In SC-FDMA, DFT output ismapped to IFFT input contiguously. On the other hand, in clusteredSC-FDMA, DFT output is divided into several clusters and mapped to IFFTinput. The intervals of these clusters will be filled with zero input.Clustered SC-FDMA will support non-contiguous frequency allocation bythis mechanism.

NxSC-FDMA is also similar to SC-FDMA. To achieve non-contiguousfrequency allocation, multiple DFTs will be used in NxSC-FDMA. Theseoutputs will be mapped to the IFFT. The output of the IFFT becomesmultiple single carrier signals.

Several different channels are defined for a 3GPP LTE system. Fortransmission on the downlink, user data is carried on the physicaldownlink shared channel (PDSCH). Downlink control signaling on thephysical downlink control channel (PDCCH) is used to convey thescheduling decisions to individual UEs. The PDCCH is located in thefirst OFDM symbols of a subframe.

Modulation and coding for the shared data channel is not fixed, but isadapted according to radio link quality. The UEs regularly reportchannel quality indicator (CQI) information to the Node B.

For transmission on the uplink, user data is carried on the physicaluplink shared channel (PUSCH). The physical uplink control channel(PUCCH) carries uplink control information, e.g., CQI reports andACK/NACK information related to data packets received in the downlink.The UE uses the PUCCH when it does not have any data to transmit on thePUSCH. If the UE has data to transmit on the PUSCH, the UE multiplexesthe control information with data on the PUSCH.

Data is allocated to the UEs in terms of resource blocks (RB). Resourceblocks are used to describe the mapping of certain physical channels toresource elements. A physical resource block is defined as a certainnumber of consecutive OFDM symbols in the time domain and a certainnumber of consecutive subcarriers in the frequency domain.

FIG. 1 illustrates a wireless communication system 100 in which thepresent systems and methods may be practiced. In a communications system100, transmission signals may be sent from a mobile station to a basestation and from a base station to a mobile station. Communications fromthe mobile station to the base station may be referred to as uplinkcommunications 106. Similarly, communications from the base station tothe mobile station may be referred to as downlink communications 108.

The present systems and methods described herein relate to 3GPP LTEAdvanced systems. However, the present systems and methods may beutilized for other communication systems such as IEEE 802.16 (WiMAX)systems, and other systems where the scheduling of users is applicable.

The base station may be referred to as a Node B 102. The mobile stationmay be referred to as user equipment (UE) 104. A Node B 102 may be inwireless communication with one or more UEs 104 (which may also bereferred to as user devices, communications devices, subscriber units,access terminals, terminals, etc.). The Node B 102 may be a unit adaptedto transmit to and receive data from cells. Although not shown, awireless communication system 100 may include more than one Node B 102and more than the three UEs 104 shown in FIG. 1.

In one example, the Node B 102 handles the communication across a radiointerface, covering a specific geographical area in the vicinity of theNode B 102, which is referred to as a cell. Depending on sectoring, oneor more cells may be served by the Node B 102, and accordingly the NodeB 102 may support one or more UEs 104 depending on where the UEs 104 arelocated. In one configuration, the Node B 102 provides a 3GPP (Release8) Long Term Evolution (LTE) air interface and performs radio resourcemanagement for the communication system 100. In another configuration,the Node B 102 provides a 3GPP LTE-Advanced air interface.

As discussed above, the Node B 102 may be in electronic communicationwith one or more UEs 104. A first UE 104 a, a second UE 104 b, and athird UE 104 c are shown in FIG. 1. The Node B 102 may transmit data tothe UEs 104 and receive data from the UEs 104 over a radio frequency(RF) communication channel.

The signals transmitted by a UE 104 may include requests for data. Thesignals transmitted by the Node B 102 may be data requested by aparticular UE 104 such as downloaded Internet data. Alternatively, thesignals transmitted by the Node B 102 and UEs 104 may include data formaintaining the wireless communication system 100. For example, the NodeB 102 may transmit reference signals to the UEs 104 requesting channelestimation and the UEs 104 may return channel estimation values to theNode B 102. Examples of possible reference signals include pilots orbeacons which may be single tone signals with a known amplitude andfrequency. Another example may be a reference signal used in current LTEsystems, which is a known (by transmitter and receiver) sequence ofsymbols used for estimating the channel. A further example of areference signal may be Zadoff-Chu sequences as described in 3GPP TS36.211 V8.2.0 (2008-03).

The Node B 102 may also transmit control information to the UEs 104. Thecontrol information may include instructions for the uplink modulationscheme to be used by a UE 104. For example, the Node B 102 may transmitcontrol information to a UE 104 that instructs the UE 104 to transmituplink information using OFDMA, SC-FDMA, clustered SC-FDMA, orNxSC-FDMA.

A scheduler on the Node B 102 may determine the service parameters, suchas the coding and modulation scheme of a UE 104 before it is served. Thescheduler may assign one or more UEs 104 to each communication channel.To perform this task, the Node B 102 may use channel quality informationof all the UEs 104 over at least a portion of the frequency band.

FIG. 2 illustrates a wireless communication system 200 in which thepresent systems and methods may be practiced. The wireless communicationsystem 200 may include a Node B 202. The Node B 202 may be in electroniccommunication with a first UE 204 a and a second UE 204 b. The Node B202 may send information to the first UE 204 a over a downlinktransmission 208 a and receive information from the first UE 204 a overan uplink transmission 206 a. Likewise, the Node B 202 may sendinformation to the second UE 204 b over a downlink transmission 208 band receive information from the second UE 204 b over an uplinktransmission 206 b.

The Node B 202 may be surrounded by one or more geographic areas. InFIG. 2, the Node B 202 is surrounded by two geographic areas, GA1 210and GA2 212. The geographic areas may define the areas within a relativedistance from the Node B 202. For example, GA1 210 may include all thearea that is within a certain radius of the Node B 202. Likewise, GA2212 may include all the area that is within a certain radius of the NodeB 202 that is not included in GA1 210. Alternatively, GA2 212 mayinclude all the area that is not included in GA1 210.

The Node B 202 may make scheduling decisions for a particular UE 204based on the location of the UE 204. For example, a UE 204 in GA1 210may receive different scheduling parameters than a UE 204 in GA2 212.The Node B 202 may determine the location of a particular UE 204 basedon the received channel quality information from the UE 204.

In FIG. 2, UE1 204 a is shown as operating within GA1 210 and UE2 204 bis shown as operating within GA2 212. The Node B 202 may instruct UE1204 a and UE2 204 b to send uplink transmissions 206 to the Node B 202.The uplink transmissions 206 a of UE1 204 a may use different modulationschemes than the uplink transmissions 206 b of UE2 204 b. For example,in LTE-Advanced, a UE 204 may make use of SC-FDMA or OFDMA/clusteredSC-FDMA/NxSC-FDMA as uplink modulation schemes. By using an OFDMAmodulation scheme, the communication system 200 may introduce advancedreceivers for receiving MIMO. When MIMO communications are used, OFDMAmay have the benefit of reducing the complexity of the receiver. SC-FDMAmay have the benefit of reducing the PAPR and/or the cubic metric (CM).Thus, it may be beneficial for UE1 204 a to use an OFDMA modulationscheme when sending uplink transmissions 206 a to the Node B 202 becauseUE1 204 a is within GA1 210 and is thus relatively close to the Node B202. Likewise, it may be beneficial for UE2 204 b to use an SC-FDMAmodulation scheme when sending uplink transmissions 206 b to the Node B202 because UE2 204 b is within GA2 212 and is thus on (or near) thecell edge.

FIG. 3 illustrates various components that may be utilized to implementthe present systems and methods. A Node B 302 is shown. The Node B 302may include downlink control information (DCI) 310 to be sent to a UE304. The DCI 310 may be transmitted to the UE 304 via a downlinktransmission 308 (e.g., via the PDCCH). A DCI 310 may be sent in aparticular format 312. For example, the DCI 310 may be in Format 1 312a, Format 1A 312 b, Format 1B 312 c, and Format 2 312 d.

DCI Format 1A is used for the scheduling of PUSCH. Table 1-1 includesexamples of information that may be transmitted by means of the DCIFormat 1A. Table 1-1 includes a column showing the field and anothercolumn for explanatory comments regarding the field.

TABLE 1-1 Field Comment Format Uplink grant or downlink assignment (Flagfor UL/DL differentiation) Hopping Flag Frequency hopping on/off RBAllocation MCS New Data Indicator Toggled for each new transport blockTPC Power control of PUSCH Cyclic Shift for DMRS FFS if always presentor not (may depend on design of format 1A) CQI Request RNTI/CRC 16 bitRNTI implicitly encoded in CRC

The format may be a flag for UL/DL (Uplink/Downlink) differentiation. Inone configuration this field may be 1 bit. The hopping flag may also be1 bit. The resource block allocation is included. The MCS is themodulation and coding scheme (and redundancy version), and it may be 5bits in one configuration. The new data indicator may be 1 bit. The TPC(Transmit Power Control) field is the command for the scheduled PUSCHand may be 2 bits. The cyclic shift for DMRS (Demodulation ReferenceSignals) may be 3 bits in one configuration. The CQI request may be 1bit. The last field shown in Table 1-1 is the RNTI/CRC (Radio NetworkTemporary Identity/Cyclic Redundancy Check) that may be a 16 bit fieldRNTI implicitly encoded in the CRC.

These are examples of possible contents of Format 1A. Format 1A mayinclude other information and/or may not include some of the aboveinformation.

DCI Format 1 is used for the scheduling of PUSCH. Table 1-2 includesexamples of information that may be transmitted by means of the DCIFormat 1. Table 1-2 includes a column showing the field and anothercolumn for explanatory comments regarding the field.

TABLE 1-2 Field Comment Format Uplink grant or downlink assignment (Flagfor UL/DL differentiation) Resource Allocation Indicates allocation type0 or 1 (type 2 uses Header payload A, same as UL) Hopping Flag Frequencyhopping on/off RB Allocation MCS New Data Indicator Toggled for each newtransport block TPC Power control of PUSCH Cyclic Shift for DMRS FFS ifalways present or not (may depend on design of format 1A) CQI RequestRNTI/CRC 16 bit RNTI implicitly encoded in CRC

The format may be a flag for UL/DL differentiation. In one configurationthis field may be 1 bit. A resource allocation header may indicate theresource allocation type (type 0 or type 1) and may also be 1 bit. Thehopping flag may also be 1 bit. The resource block allocation isincluded. The MCS is the modulation and coding scheme (and redundancyversion), and it may be 5 bits in one configuration. The new dataindicator may be 1 bit. The TPC field is the command for the scheduledPUSCH and may be 2 bits. The cyclic shift for DMRS may be 3 bits in oneconfiguration. The CQI request may be 1 bit. The last field shown inTable 1-2 is the RNTI/CRC (Radio Network Temporary Identity/CyclicRedundancy Check) that may be a 16 bit field RNTI implicitly encoded inthe CRC.

These are examples of possible contents of Format 1. Format 1 mayinclude other information and/or may not include some of the aboveinformation. DCI Format 1B is used for the scheduling of PUSCH. Table1-3 includes examples of information that may be transmitted by means ofthe DCI Format 1B. Table 1-3 includes a column showing the field andanother column for explanatory comments regarding the field.

TABLE 1-3 Field Comment Format Uplink grant or downlink assignment (Flagfor UL/DL differentiation) Hopping Flag Frequency hopping on/off RBAllocation MCS Precoding Information Preceding matrix (4 bits for 4Tx,1-3 bits for 2Tx). FFS if this field can be removed and semi-staticconfiguration is used instead. New Data Indicator Toggled for each newtransport block TPC Power control of PUSCH Cyclic Shift for DMRS FFS ifalways present or not (may depend on design of format 1A) CQI RequestRNTI/CRC 16 bit RNTI implicitly encoded in CRC

The format may be a flag for UL/DL differentiation. In one configurationthis field may be 1 bit. The hopping flag may also be 1 bit. Theresource block allocation is included. The MCS is the modulation andcoding scheme (and redundancy version), and it may be 5 bits in oneconfiguration. The preceding information or Precoding Matrix Index (PMI)may also be included. included. The new data indicator may be 1 bit. TheTPC field is the command for the scheduled PUSCH and may be 2 bits. Thecyclic shift for DMRS may be 3 bits in one configuration. The CQIrequest may be 1 bit. The last field shown in Table 1-3 is the RNTI/CRCthat may be a 16 bit field RNTI implicitly encoded in the CRC.

These are examples of possible contents of Format 1B. Format 1B mayinclude other information and/or may not include some of the aboveinformation.

DCI Format 2 is used for the scheduling of PUSCH. Table 1-4 includesexamples of information that may be transmitted by means of the DCIFormat 2. Table 1-4 includes a column showing the field and anothercolumn for explanatory comments regarding the field.

TABLE 1-4 Field Comment Format Uplink grant or downlink assignment (Flagfor UL/DL differentiation) Resource Allocation Indicates allocation type0 or 1 (type 2 uses Header payload A, same as UL) Hopping Flag Frequencyhopping on/off RB Allocation Number of Layers 1, 2, 3, 4 layers. Numberof bits may depend on the number of Tx antennas (2 for 4Tx, 0otherwise). Also may depend on the number of Rx antennas in the UE.Precoding Information Precoding matrix (4 bits for 4Tx, 1-3 bits for2Tx). FFS if this field can be removed and semi-static configuration isused instead. MCS, first transport block MCS, second transport block NewData Indicator (1^(st) Toggled for each new transport block TB) New DataIndicator (2^(nd) Toggled for each new transport block TB) HARQ SwapFlag Indicates whether the two transport blocks should be swapped beforebeing fed to the soft buffers (for the two transport blocks) TPC Powercontrol of PUSCH Cyclic Shift for DMRS FFS if always present or not (maydepend on design of format 1A) CQI Request RNTI/CRC 16 bit RNTIimplicitly encoded in CRC

The format may be a flag for UL/DL (Uplink/Downlink) differentiation. Inone configuration this field may be 1 bit. A resource allocation headermay indicate the resource allocation type (type 0 or type 1) and mayalso be 1 bit. The hopping flag may also be 1 bit. The resource blockallocation is included. The number of layers may indicate the number oflayers. The number of bits for the number of layers field may depend onvarious factors including the number of antennas. The precedinginformation or Precoding Matrix Index (PMI) may also be included. Theremay be two codewords or two transport blocks. The MCS for the firsttransport block is the modulation and coding scheme (and redundancyversion) for the first transport block, and it may be 5 bits in oneconfiguration. There may also be an MCS for the second transport block.The new data indicator for the first transport block may be 1 bit. Thenew data indicator for the second transport block may also be 1 bit.

An HARQ (hybrid automatic repeat request) Swap Flag may indicate whetherthe two transport blocks should be swapped before being fed to the softbuffers (for the two transport blocks). The TPC field is the command forthe scheduled PUSCH and may be 2 bits. The cyclic shift for DMRS may be3 bits in one configuration. The CQI request may be 1 bit. The lastfield shown in Table 1-4 is the RNTI/CRC that may be a 16 bit field RNTIimplicitly encoded in the CRC.

These are examples of possible contents of Format 2. Format 2 mayinclude other information and/or may not include some of the aboveinformation.

The meaning of the DCI formats 312 are described in more detail in 3GPPTS 36.212 v8.2.0 which applies to 3GPP LTE. LTE-Advanced is an extensionof LTE. The pertinent DCI formats 312 are shown in Table 1-5. The DCIformats 312 may include assignments for the uplink data transmission.For example, the DCI formats 312 may include contiguous RB allocation,non-contiguous RB allocation, modulation and coding schemes (MCS), and apreceding matrix index (PMI).

TABLE 1-5 RB Allocation Contents Format 1 Non-Contiguous RB allocation,MCS, etc. Format 1A Contiguous RB allocation, MCS, etc. Format 1BContiguous RB allocation, MCS, PMI, etc. Format 2 Non-Contiguous RBallocation, MCS for codeword 1, MCS for codeword 2, PMI, etc.

Table 1-5 illustrates that Format 1B 312 c and Format 2 312 d includePMI information. Format 1B 312 c includes only one piece of MCSinformation while Format 2 312 d includes two pieces of MCS information.The Node B 302 may include a format selection module 320 for selectingthe appropriate DCI format 312 to be transmitted to the UE 304.

The format 312 of the DCI 310 may depend on the transmission mode 328 ofthe UE 304. Table 2 lists the transmission modes 328 and thecorresponding DCI formats 312. The transmission mode 328 of the UE 304is assumed to be configured by the Node B 302 via radio resource control(RRC) signaling. Format 1 312 a and Format 1A 312 b may be used forsingle input multiple output (SIMO) transmissions such as transmitdiversity and beamforming. Format 2 312 d and Format 1A 312 b may beused for single user-MIMO (SU-MIMO) transmissions. Format 1B 312 c andFormat 1A 312 b may be used for multiple user-MIMO (MU-MIMO)transmissions or RANK-1 SU-MIMO. RANK-1 SU-MIMO is a subset of SU-MIMO.The difference between SU-MIMO and RANK-1 SU-MIMO is that there is nolayer multiplexing and only one codeword will be transmitted in RANK-1SU-MIMO.

TABLE 2 Transmission Mode Formats Single Antenna/Transmission Format1/Format 1A Diversity/Beamforming SU-MIMO Format 2/Format 1A MU-MIMOFormat 1B/Format 1A

User equipment (UE) 304 is also shown in FIG. 3. The UE 304 may includea received DCI 310. The DCI 310 may be received from the Node B 302. TheUE 304 may also include a format decoder 324. The format decoder 324 maybe configured to determine the format of the received DCI 310. The UE304 may include an uplink data transmission table 326. The uplink datatransmission table 326 may be configured to specify the uplinkmodulation scheme for the UE 304 according to the format of the receivedDCI 310. For example, the uplink data transmission table 326 may specifythat the UE 304 is to use OFDMA as the uplink modulation scheme forcertain formats of received DCI 310 and SC-FDMA for other formats ofreceived DCI 310. Examples of uplink data transmission tables 326 usedin the present systems and methods are shown in Table 3, Table 4, andTable 5.

TABLE 3 Uplink Modulation RB Allocation Contents Scheme Format 1Non-Contiguous RB allocation, MCS, etc. OFDMA Format 1A Contiguous RBallocation, MCS, etc. SC-FDMA Format 1B Contiguous RB allocation, MCS,OFDMA PMI, etc. Format 2 Non-Contiguous RB allocation, MCS for OFDMAcodeword 1, MCS for codeword 2, PMI, etc.

TABLE 4 Uplink Modulation RB Allocation Contents Scheme Format 1Non-Contiguous RB allocation, MCS, etc. OFDMA Format 1A Contiguous RBallocation, MCS, etc. SC-FDMA Format 1B Contiguous RB allocation, MCS,SC-FDMA PMI, etc. Format 2 Non-Contiguous RB allocation, MCS for OFDMAcodeword 1, MCS for codeword 2, PMI, etc.

TABLE 5 Uplink Modulation RB Allocation Contents Scheme Format 1Non-Contiguous RB allocation, MCS, etc. OFDMA Format 1A Contiguous RBallocation, MCS, etc. SC-FDMA Format 1B Contiguous RB allocation, MCS,SC-FDMA/ PMI, SC-FDMA/OFDMA OFDMA switching bit, etc. Format 2Non-Contiguous RB allocation, MCS for OFDMA codeword 1, MCS for codeword2, PMI, etc.

As discussed above, the UE 304 may operate in different transmissionmodes 328. For example, the UE 304 may operate in single antenna mode330, transmission diversity mode 332, beamforming mode 334, SU-MIMO mode336, and MU-MIMO mode 338. The Node B 302 may select the format of theDCI 310 according to the transmission mode 328 of the UE 304. Uponselection of a modulation scheme for the uplink transmission 306, the UE304 may then send an uplink transmission 306 to the Node B 302 accordingto the selected modulation scheme. Thus, the uplink transmission 306 maybe modulated according to SC-FDMA or OFDMA/clustered SC-FDMA/NxSC-FDMA.

FIG. 4 is a flow diagram illustrating a method 400 for switching betweenSC-FDMA and OFDMA as the uplink modulation scheme. The method 400 ofFIG. 4 may also be applied to switching between SC-FDMA and clusteredSC-FDMA, and to switching between SC-FDMA and NxSC-FDMA. The UE 304 mayreceive 402 a DCI 310. The UE 304 may decode 404 the format 312 of theDCI 310. The UE 304 may then determine 406 the uplink modulation schemeby comparing the format of the received DCI 310 with the uplink datatransmission table 326. The UE 304 may select 408 the appropriate uplinkmodulation scheme. The UE 304 may then transmit 410 the uplink datasignal according to the uplink modulation scheme.

FIG. 5 is a flow diagram illustrating a more detailed method 500 forswitching between SC-FDMA and OFDMA as the uplink modulation scheme.Although not shown, the method 500 of FIG. 5 may also be applied toswitching between SC-FDMA and clustered SC-FDMA, and to switchingbetween SC-FDMA and NxSC-FDMA. The UE 304 may receive 502 a DCI 310. TheUE 304 may determine 504 whether the received DCI 310 includes anon-contiguous RB allocation. If the DCI 310 includes a non-contiguousRB allocation, the UE 304 may select 508 OFDMA as the uplink modulationscheme. The UE 304 may then transmit 510 signals according to the OFDMAmodulation scheme. If the DCI 310 does not include a non-contiguous RBallocation, the UE 304 may determine 506 whether the received DCI 310includes PMI information. If the received DCI 310 includes PMIinformation, the UE 304 may select 508 OFDMA as the uplink modulationscheme and transmit 510 signals according to the OFDMA modulationscheme. If the received DCI 310 does not include PMI information, the UE304 may select 512 SC-FDMA as the uplink modulation scheme. The UE 304may then transmit 514 signals according to the SC-FDMA modulationscheme.

FIG. 6 is a flow diagram illustrating an alternative method 600 forswitching between SC-FDMA and OFDMA as the uplink modulation scheme.Although not shown, the method 600 of FIG. 6 may also be applied toswitching between SC-FDMA and clustered SC-FDMA, and to switchingbetween SC-FDMA and NxSC-FDMA. The UE 304 may receive 602 a DCI 310. TheUE 304 may determine 604 whether the received DCI 310 includes anon-contiguous RB allocation. If the DCI 310 includes a non-contiguousRB allocation, the UE 304 may select 608 OFDMA as the uplink modulationscheme and may then transmit 610 signals according to the OFDMAmodulation scheme. If the DCI 310 does not include a non-contiguous RBallocation, the UE 304 may select 612 SC-FDMA as the uplink modulationscheme. The UE 304 may then transmit 614 signals according to theSC-FDMA modulation scheme.

FIG. 7 is a flow diagram illustrating another method 700 for switchingbetween SC-FDMA and OFDMA as the uplink modulation scheme. Although notshown, the method 700 of FIG. 7 may also be applied to switching betweenSC-FDMA and clustered SC-FDMA, and to switching between SC-FDMA andNxSC-FDMA. The UE 304 may first receive 702 a DCI 310. The UE 304 maydetermine 704 whether the received DCI 310 includes a non-contiguous RBallocation. If the DCI 310 includes a non-contiguous RB allocation, theUE 304 may select 712 OFDMA as the uplink modulation scheme. If the DCI310 does not include a non-contiguous RB allocation, the UE 304 may thendetermine 706 whether the DCI 310 includes PMI information.

If the DCI 310 does not include PMI information, the UE 304 may select716 SC-FDMA as the uplink modulation scheme. If the DCI 310 does includePMI information, the UE 304 may determine 708 whether the DCI 310includes only one MCS. If the DCI 310 does not include only one MCS (andthus includes more than one MCS), the UE 304 may select 712 OFDMA as theuplink modulation scheme. If the DCI 310 does include only one MCS, theformat of the DCI 310 is Format 1B 312 c and the UE 304 may determine710 whether the switching bit in Format 1B 312 c is set to OFDMA orSC-FDMA. If the switching bit in Format 1B 312 c is set to OFDMA, the UE304 may select 712 OFDMA as the uplink modulation scheme. If theswitching bit in Format 1B 312 c is set to SC-FDMA, the UE 304 mayselect 716 SC-FDMA as the uplink modulation scheme.

Once the UE 304 has selected OFDMA as the uplink modulation scheme, theUE 304 may transmit 714 signals on the uplink according to the OFDMAmodulation scheme. Likewise, once the UE 304 has selected SC-FDMA as theuplink modulation scheme, the UE 304 may transmit 718 signals on theuplink according to the SC-FDMA modulation scheme.

FIG. 8 illustrates L1/L2 signaling between the Node B 802 and the UE804. L1/L2 signaling is the sending of control information from the NodeB 802 to the UE 804 via the PDCCH. The UE 804 sends CQI feedback to theNode B 802 via the PUCCH/PUSCH 806. The Node B 802 sends controlinformation to the UE 804 via the PDCCH 808. The control information onthe PDCCH 808 may include a DCI 310 to instruct the UE 804 whether toselect SC-FDMA or OFDMA as the uplink modulation scheme. The UE 804 maythen send the uplink data transmission via the PUSCH 810. The uplinkdata transmission on the PUSCH 810 may be modulated according to theselected uplink modulation scheme.

FIG. 9 illustrates the RB allocation of an LTE uplink transmission. TheRB allocation may be a contiguous allocation in an SC-FDMA transmissionsuch as Format 1A 312 b and Format 1B 312 c. Both edges of the systembandwidth are allocated to PUCCH 902, 906 and the interior bandwidth isallocated to PUSCH 904. The sub-band for an LTE RB in a Release 8 UE is20 MHz. In LTE-Advanced systems, the system bandwidth may be expanded to40 MHz or more. Because LTE-Advanced requires backwards compatibilitywith LTE, the spectrum allocation for LTE-Advanced UEs will benon-contiguous when the bandwidth is larger than 20 MHz due to theallocation of the spectrum edges to PUCCH 902, 906.

One way for achieving a system that is configured in accordance with theLTE-Advanced standard is to concatenate LTE systems in the frequencydomain. By concatenating LTE systems in the frequency domain, anLTE-Advanced system can use wide bandwidth as one system bandwidth andcan achieve higher throughputs. However, the UE 304 cannot transmituplink data in RBs which have been allocated to PUCCH 902, 906. This maycause a conflict between PUSCH 904 signals and the PUCCH 902, 906signals of other UEs, especially if Format 1A's RB allocation includesRBs which are allocated to PUCCH 902, 906. In LTE-Advanced, the RBs forSC-FDMA are allocated consecutively but the spectrum allocation forLTE-Advanced UEs will be non-contiguous when the bandwidth is largerthan 20 MHz.

One solution to this problem is to implement clustered SC-FDMA. Inclustered SC-FDMA, the output of the DFT (discrete Fourier transform) ismapped to the input of the IFFT (inverse fast Fourier transform). Inthis UL access scheme, DFT output may be divided to several clusters andmapped to IFFT. The intervals of these clusters may be filled with zeroinput. In other words, the intervals of these clusters will bepunctured. Clustered SC-FDMA will support non-contiguous frequencyallocation by this mechanism.

FIG. 10 illustrates the RB allocation of an LTE-Advanced uplinktransmission. This solution to the conflict between PUSCH signals andother UE's PUCCH signals is to puncture the RBs which are allocated tothe PUCCH by using clustered SC-FDMA as described above. This means thatno allocation is given to the input of the IFFT. Thus, in the RBallocation that is signaled via PDCCH, the UE 304 automatically removesthe allocation for the PUCCH RBs 1002 a, 1002 b, 1006 a, 1006 b. Inother words, the UE 304 will not send any signal on the PUCCH RBs 1002a, 1002 b, 1006 a, 1006 b.

In order to avoid sending any signals on the PUCCH RBs 1002 a, 1002 b,1006 a, 1006 b, the UE 304 may find out the exact RBs 1002 a, 1002 b,1006 a, 1006 b which are allocated to the PUCCH. The UE 304 may use the“Maximum SRS bandwidth” and/or the “PUCCH resource size” to determinethe exact RBs 1002 a, 1002 b, 1006 a, 1006 b which are allocated to thePUCCH. The UE 304 may receive the “Maximum SRS bandwidth” and the “PUCCHresource size” via RRC signaling on the broadcast channel (BCH). The UE304 may then use the formats in Table 3, Table 4, and Table 5 topuncture the RBs 1002 a, 1002 b, 1006 a, 1006 b which are allocated tothe PUCCH. Thus, the UE 304 may automatically remove the RBs 1002 a,1002 b, 1006 a, 1006 b that are allocated to the PUCCH and only transmitthe uplink on the remaining PUSCH RBs 1008, 1010.

Moreover, Format 1A and 1B in Table 3, 4 and 5 can be used to inform thewide RB allocation, e.g. RB allocation which is wider than 20 MHz or RBallocation which includes PUCCH RBs, by using this solution. Otherwise,non-contiguous RB allocation, e.g. Format 1 in Table 3, has to be usedto inform the above wide RB allocation to avoid the conflicts with PUCCHRBs.

The clustered SC-FDMA solution may be used to avoid the conflict withPUCCH RBs as in the above. However, systems and methods may also useNxSC-FDMA or OFDMA instead of Clustered SC-FDMA.

FIG. 11 is a block diagram of a UE 1104 in accordance with oneconfiguration of the described systems and methods. The UE 1104 may alsobe referred to as a mobile station, a subscriber station, an accessterminal, a remote station, etc. The UE 1104 may include a transceiver1120 that includes a transmitter 1110 and a receiver 1112. Thetransceiver 1120 may be coupled to one or more antennas 1118. The UE1104 may further include a digital signal processor (DSP) 1114, ageneral purpose processor 1116, memory 1108, and a communicationsinterface 1124. The various components of the UE 1104 may be includedwithin a housing 1122.

The processor 1116 may control operation of the UE 1104. The processor1116 may also be referred to as a CPU. The memory 1108, which mayinclude both read-only memory (ROM) and random access memory (RAM),provides instructions 1136 and data 1134 to the processor 1116. Aportion of the memory 1108 may also include non-volatile random accessmemory (NVRAM). The memory 1108 may include any electronic componentcapable of storing electronic information, and may be embodied as ROM,RAM, magnetic disk storage media, optical storage media, flash memory,on-board memory included with the processor 1116, EPROM memory, EEPROMmemory, registers, a hard disk, a removable disk, a CD-ROM, etc.

The memory 1108 may store program instructions 1136 and other types ofdata 1134. For example, the memory 1108 may store program instructions1136 such as instructions 1150 for receiving a DCI 1140, andinstructions 1152 for decoding the format of the received DCI 1140. Theformat of the DCI 1140 may depend on the transmission mode 1144. Theprogram instructions 1136 may also include instructions 1154 fordetermining the uplink modulation scheme according to the DCI format. Anuplink data transmission table 1142 may be configured to specify theuplink modulation scheme for the UE 1104 according to the format of thereceived DCI 1140. The program instructions 1136 may also includeinstructions 1156 for selecting an uplink modulation scheme, andinstructions 1158 for transmitting the uplink signal according to theselected uplink modulation scheme. The program instructions 1136 mayalso include instructions 1160 for determining if the DCI 1140 includesa non-contiguous RB allocation, instructions 1162 for determining if theDCI 1140 includes a PMI, instructions 1164 for determining if the DCI1140 includes an MCS, and instructions 1166 for determining the DCIswitching bit setting.

Other types of instructions 1136 and data 1134 that are relevant toimplementing the techniques described herein may also be included in thememory 1108.

The program instructions 1136 may be executed by the processor 1116 toimplement some or all of the methods disclosed herein. The processor1116 may also use the data 1134 stored in the memory 1108 to implementsome or all of the methods disclosed herein. As a result, instructions1136 and data 1134 may be loaded and/or otherwise used by the processor1116.

In accordance with the disclosed systems and methods, the antenna 1118may receive downlink signals that have been transmitted from a nearbycommunications device, such as a Node B 102. The antenna 1118 providesthese received signals to the transceiver 1120 which filters andamplifies the signals. The signals are provided from the transceiver1120 to the DSP 1114 and to the general purpose processor 1116 fordemodulation, decoding, further filtering, etc.

The various components of the UE 1104 are coupled together by a bussystem 1126 which may include a power bus, a control signal bus, and astatus signal bus in addition to a data bus. However, for the sake ofclarity, the various busses are illustrated in FIG. 11 as the bus system1126.

FIG. 12 is a block diagram of a base station 1202 in accordance with oneconfiguration of the described systems and methods. The base station1202 may also be referred to as a node B (NB), a base stationcontroller, a base station transceiver, etc.

The base station 1202 includes many components that are similar to thecomponents of the UE 1104 of FIG. 11, including a processor 1216, memory1208 storing both data 1234 and instructions 1236, a transceiver 1220including a transmitter 1210 and a receiver 1212, an antenna 1218, asystem bus 1226, a DSP 1214, a communications interface 1224, and ahousing 1222.

The memory 1208 may store instructions 1250 for determining the UElocation 1242, instructions 1252 for determining the UE uplinkmodulation scheme to be used, instructions 1254 for determining the DCIformat that corresponds to the UE uplink modulation scheme, andinstructions 1256 for sending the DCI 1240 to the UE according to theDCI format.

Other types of instructions 1236 and data 1234 that are relevant toimplementing the techniques described herein may also be included in thememory 1208.

In accordance with the disclosed systems and methods, the antenna 1218may receive uplink signals that have been transmitted from a nearbycommunications device, such as a UE 1104. The antenna 1218 providesthese received signals to the transceiver 1220 which filters andamplifies the signals. The signals are provided from the transceiver1220 to the DSP 1214 and to the general purpose processor 1216 fordemodulation, decoding, further filtering, etc.

In the above description, reference numbers have sometimes been used inconnection with various terms. Where a term is used in connection with areference number, this is meant to refer to a specific element that isshown in one or more of the Figures. Where a term is used without areference number, this is meant to refer generally to the term withoutlimitation to any particular Figure. For example, a reference to “basestation 1202” refers to the specific base station that is shown in FIG.12. However, the use of “base station” without a reference number refersto any base station that is appropriate for the context in which theterm is used, and is not limited to any particular base station shown inthe Figures.

As used herein, the term “determining” encompasses a wide variety ofactions and, therefore, “determining” can include calculating,computing, processing, deriving, investigating, looking up (e.g.,looking up in a table, a database or another data structure),ascertaining and the like. Also, “determining” can include receiving(e.g., receiving information), accessing (e.g., accessing data in amemory) and the like. Also, “determining” can include resolving,selecting, choosing, establishing and the like.

The phrase “based on” does not mean “based only on,” unless expresslyspecified otherwise. In other words, the phrase “based on” describesboth “based only on” and “based at least on.”

The term “processor” should be interpreted broadly to encompass ageneral purpose processor, a central processing unit (CPU), amicroprocessor, a digital signal processor (DSP), a controller, amicrocontroller, a state machine, and so forth. Under somecircumstances, a “processor” may refer to an application specificintegrated circuit (ASIC), a programmable logic device (PLD), a fieldprogrammable gate array (FPGA), etc. The term “processor” may refer to acombination of processing devices, e.g., a combination of a DSP and amicroprocessor, a plurality of microprocessors, one or moremicroprocessors in conjunction with a DSP core, or any other suchconfiguration.

The term “memory” should be interpreted broadly to encompass anyelectronic component capable of storing electronic information. The termmemory may refer to various types of processor-readable media such asrandom access memory (RAM), read-only memory (ROM), non-volatile randomaccess memory (NVRAM), programmable read-only memory (PROM), erasableprogrammable read only memory (EPROM), electrically erasable PROM(EEPROM), flash memory, magnetic or optical data storage, registers,etc. Memory is said to be in electronic communication with a processorif the processor can read information from and/or write information tothe memory. Memory that is integral to a processor is in electroniccommunication with the processor.

The terms “instructions” and “code” should be interpreted broadly toinclude any type of computer-readable statement(s). For example, theterms “instructions” and “code” may refer to one or more programs,routines, sub-routines, functions, procedures, etc. “Instructions” and“code” may comprise a single computer-readable statement or manycomputer-readable statements. The terms “instructions” and “code” may beused interchangeably herein.

The functions described herein may be implemented in hardware, software,firmware, or any combination thereof. If implemented in software, thefunctions may be stored as one or more instructions on acomputer-readable medium. The term “computer-readable medium” refers toany available medium that can be accessed by a computer. By way ofexample, and not limitation, a computer-readable medium may compriseRAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic diskstorage or other magnetic storage devices, or any other medium that canbe used to carry or store desired program code in the form ofinstructions or data structures and that can be accessed by a computer.Disk and disc, as used herein, includes compact disc (CD), laser disc,optical disc, digital versatile disc (DVD), floppy disk and Blu-ray®disc where disks usually reproduce data magnetically, while discsreproduce data optically with lasers.

Software or instructions may also be transmitted over a transmissionmedium. For example, if the software is transmitted from a website,server, or other remote source using a coaxial cable, fiber optic cable,twisted pair, digital subscriber line (DSL), or wireless technologiessuch as infrared, radio, and microwave, then the coaxial cable, fiberoptic cable, twisted pair, DSL, or wireless technologies such asinfrared, radio, and microwave are included in the definition oftransmission medium.

The methods disclosed herein comprise one or more steps or actions forachieving the described method. The method steps and/or actions may beinterchanged with one another without departing from the scope of theclaims. In other words, unless a specific order of steps or actions isrequired for proper operation of the method that is being described, theorder and/or use of specific steps and/or actions may be modifiedwithout departing from the scope of the claims.

It is to be understood that the claims are not limited to the preciseconfiguration and components illustrated above. Various modifications,changes and variations may be made in the arrangement, operation anddetails of the systems, methods, and apparatus described herein withoutdeparting from the scope of the claims.

1. A method for selection of an uplink modulation scheme, the methodbeing implemented by user equipment (UE), the method comprising:receiving downlink control information (DCI); decoding a format of theDCI; determining an uplink modulation scheme according to the format ofthe DCI; selecting the uplink modulation scheme; and transmitting anuplink signal according to the uplink modulation scheme.
 2. The methodof claim 1, wherein the uplink modulation scheme is single carrierfrequency division multiple access (SC-FDMA).
 3. The method of claim 1,wherein the uplink modulation scheme is orthogonal frequency divisionmultiple access (OFDMA).
 4. The method of claim 1, wherein the uplinkmodulation scheme is N (N is a natural number) times single carrierfrequency division multiple access (NXSC-FDMA).
 5. The method of claim1, wherein the uplink modulation scheme is clustered single carrierfrequency division multiple access (Clustered SC-FDMA).
 6. The method ofclaim 1, wherein decoding the format of the DCI comprises determining ifthe DCI includes a non-contiguous resource block (RB) allocation.
 7. Themethod of claim 6, wherein decoding the format of the DCI furthercomprises determining if the DCI includes a preceding matrix index(PMI).
 8. The method of claim 7, wherein decoding the format of the DCIfurther comprises determining if the DCI includes only one modulationand coding scheme (MCS).
 9. The method of claim 8, wherein the uplinkmodulation scheme is selected according to a DCI switching bit.
 10. Themethod of claim 1, wherein the UE is configured for operation in a 3GPPLTE-Advanced system, wherein the uplink modulation scheme is orthogonalfrequency division multiple access (OFDMA) or clustered single carrierfrequency division multiple access (Clustered SC-FDMA) or N (N is anatural number) times single carrier frequency division multiple access(NxSC-FDMA) if the DCI format includes non-contiguous RB (resourceblock) allocation and/or a preceding matrix index (PMI), and wherein theuplink modulation scheme is single carrier frequency division multipleaccess (SC-FDMA) if the DCI format does not include non-contiguous RBallocation or a PMI.
 11. The method of claim 1, wherein the UE isconfigured for operation in a 3GPP LTE-Advanced system, wherein theuplink modulation scheme is orthogonal frequency division multipleaccess (OFDMA) or clustered single carrier frequency division multipleaccess (Clustered SC-FDMA) or N (N is a natural number) times singlecarrier frequency division multiple access (NXSC-FDMA) if the DCI formatincludes non-contiguous RB (resource block) allocation, and wherein theuplink modulation scheme is single carrier frequency division multipleaccess (SC-FDMA) if the DCI format includes contiguous RB allocation.12. The method of claim 1, wherein the UE is configured for operation ina 3GPP LTE-Advanced system, wherein the uplink modulation scheme isorthogonal frequency division multiple access (OFDMA) or clusteredsingle carrier frequency division multiple access (Clustered SC-FDMA) orN (N is a natural number) times single carrier frequency divisionmultiple access (NXSC-FDMA) if the DCI format includes non-contiguous RB(resource block) allocation, wherein the uplink modulation scheme issingle carrier frequency division multiple access (SC-FDMA) if the DCIformat does not include non-contiguous RB allocation and a precedingmatrix index (PMI), and wherein the uplink modulation scheme is eitherOFDMA or SC-FDMA depending on a switching bit in the DCI if the DCIformat includes contiguous RB allocation and a preceding matrix index(PMI).
 13. The method of claim 1, wherein determining the uplinkmodulation scheme comprises comparing the DCI format to an uplink datatransmission table.
 14. The method of claim 13, further comprising usingformats in the uplink data transmission table to puncture resourcesallocated to the physical uplink control channel (PUCCH).
 15. The methodof claim 14, wherein puncturing resources will be communicated to the UEvia radio resource control (RRC) signaling.
 16. The method of claim 15,wherein RRC signaling means “Maximum SRS bandwidth” and/or “PUCCHResource size” on a broadcast channel (BCH).
 17. The method of claim 1,wherein the method is carried out by a user equipment (UE) using L1/L2signaling.
 18. A user equipment (UE) that is configured for selecting anuplink modulation scheme, the UE comprising: a processor; memory inelectronic communication with the processor; instructions stored in thememory, the instructions being executable to: receive downlink controlinformation (DCI); decode a format of the DCI; determine an uplinkmodulation scheme according to the format of the DCI; select the uplinkmodulation scheme; and transmit an uplink signal according to the uplinkmodulation scheme.
 19. The UE of claim 18, wherein the uplink modulationscheme is single carrier frequency division multiple access (SC-FDMA).20. The UE of claim 18, wherein the uplink modulation scheme isorthogonal frequency division multiple access (OFDMA).
 21. The UE ofclaim 18, wherein the uplink modulation is N (N is a natural number)times single carrier frequency division multiple access (NxSC-FDMA). 22.The UE of claim 18, wherein the uplink modulation scheme is clusteredsingle carrier frequency division multiple access (Clustered SC-FDMA).23. The UE of claim 18, wherein decoding the format of the DCI comprisesdetermining if the DCI includes a non-contiguous resource block (RB)allocation.
 24. The UE of claim 23, wherein decoding the format of theDCI further comprises determining if the DCI includes a preceding matrixindex (PMI).
 25. The UE of claim 24, wherein decoding the format of theDCI further comprises determining if the DCI includes only onemodulation and coding scheme (MCS).
 26. The UE of claim 25, wherein theuplink modulation scheme is selected according to a DCI switching bit.27. The UE of claim 18, wherein the UE is configured for operation in a3GPP LTE-Advanced system, wherein the uplink modulation scheme isorthogonal frequency division multiple access (OFDMA) or clusteredsingle carrier frequency division multiple access (Clustered SC-FDMA) orN (N is a natural number) times single carrier frequency divisionmultiple access (NxSC-FDMA) if the DCI format includes non-contiguous RB(resource block) allocation and/or a preceding matrix index (PMI), andwherein the uplink modulation scheme is single carrier frequencydivision multiple access (SC-FDMA) if the DCI format does not includenon-contiguous RB allocation or a PMI.
 28. The UE of claim 18, whereinthe UE is configured for operation in a 3GPP LTE-Advanced system,wherein the uplink modulation scheme is orthogonal frequency divisionmultiple access (OFDMA) or clustered single carrier frequency divisionmultiple access (Clustered SC-FDMA) or N (N is a natural number) timessingle carrier frequency division multiple access (NxSC-FDMA) if the DCIformat includes non-contiguous RB (resource block) allocation, andwherein the uplink modulation scheme is single carrier frequencydivision multiple access (SC-FDMA) if the DCI format includes contiguousRB allocation.
 29. The UE of claim 18, wherein the UE is configured foroperation in a 3GPP LTE-Advanced system, wherein the uplink modulationscheme is orthogonal frequency division multiple access (OFDMA) orclustered single carrier frequency division multiple access (ClusteredSC-FDMA) or N (N is a natural number) times single carrier frequencydivision multiple access (NxSC-FDMA) if the DCI format includesnon-contiguous RB (resource block) allocation, wherein the uplinkmodulation scheme is single carrier frequency division multiple access(SC-FDMA) if the DCI format does not include non-contiguous RBallocation and a preceding matrix index (PMI), and wherein the uplinkmodulation scheme is either OFDMA or SC-FDMA depending on a switchingbit in the DCI if the DCI format includes contiguous RB allocation and apreceding matrix index (PMI).
 30. The UE of claim 18, whereindetermining the uplink modulation scheme comprises comparing the DCIformat to an uplink data transmission table.
 31. The UE of claim 30,wherein the instructions are further executable to use formats in theuplink data transmission table to puncture resources allocated to thephysical uplink control channel (PUCCH).
 32. The UE of claim 31, whereinpuncturing resources will be communicated to the UE via radio resourcecontrol (RRC) signaling.
 33. The UE of claim 32, wherein RRC signalingmeans “Maximum SRS bandwidth” and/or “PUCCH Resource size” on abroadcast channel (BCH).
 34. A base station that is configured forselecting an uplink modulation scheme in a wireless communicationssystem, the base station comprising: a processor; memory in electroniccommunication with the processor; instructions stored in the memory, theinstructions being executable to: determine a location of a userequipment (UE); determine an uplink modulation scheme to be used by theUE; select a format for downlink control information (DCI), wherein theformat of the DCI corresponds to the uplink modulation scheme; andtransmit the DCI to the UE.
 35. The base station of claim 34, whereinthe base station is configured for operation in a 3GPP LTE-Advancedsystem.
 36. The base station of claim 34, wherein the format of the DCIis selected based on a transmission mode of the UE.
 37. The base stationof claim 34, wherein the format of the DCI is selected based on thelocation of the UE.
 38. The base station of claim 34, wherein theinstructions are further executable to transmit the DCI to the UE usingL1/L2 signaling.
 39. A computer-readable medium comprising executableinstructions for: receiving downlink control information (DCI); decodinga format of the DCI; determining an uplink modulation scheme accordingto the format of the DCI; selecting the uplink modulation scheme; andtransmitting an uplink signal according to the uplink modulation scheme.